The invention relates to a flushing arrangement for a metallurgical vessel whose bottom and walls are lined by refractory bricks arranged in rows.
By blowing flush gas into a metal melt, e.g., through the bottom of a metallurgical vessel, a stirring effect may be achieved in the metal melt, by which imbalances of composition and temperature are balanced out, the separation of non-metallic inclusions is effected and a certain degassing of the metal melt is promoted.
For introducing flush gas, a plurality of arrangements are known. Thus, e.g., Radex Rundschau, Vol. 3, 1981, p. 499 to 517; European patent application No. 0 053 554 and European patent application No. 0 032 350 show gas-permeable, refractory converter flushing bricks to be known, where such a gas flushing brick is inserted instead of a brick of the refractory lining of the converter. The flushing brick, includes a porous refractory mass with a sheet or plate jacket for avoiding a lateral gas emergence, the porous mass possibly having a directed porosity, thus replaces a conventional brick of the inner lining of the converter. The sheet or plate jacket is open towards the inner space of the converter, and at the oppositely directed end of the flushing brick, at which the sheet or plate jacket is closed, a supply duct is connected to the sheet or plate jacket in a gas-tight manner. Flushing bricks of this type have the disadvantage that they are complicated with regard to their production and installation and that an uncontrolled gas penetration may occur between the sheet or plate jacket and the porous, refractory mass contained therein, if the refractory mass does not completely abut the sheet or plate jacket. Furthermore, such a flushing brick is worn more quickly than the inner lining of the converter, necessitating repair measures costly with regard to material and time between two relinings of the inner lining.
Furthermore, it is known (Austrian patent No. 265,341) to embed a nozzle tube in a refractory flushing brick, which has, however, the disadvantage that the flushing brick, which also is inserted instead of a conventional brick of the refractory lining of the converter, must always be supplied with a certain minimum amount of flush gas as long as the flushing brick is covered by melt in order to prevent a clogging of the nozzle tube due to the penetration of melt.
Furthermore, it is known (European patent application No. 0 043 338, European patent application No. 0 021 861 and European patent application No. 0 043 787) to form a flushing brick of a number of refractory individual parts having a slight or no porosity, wherein the individual parts are held together by a sheet or plate jacket to form a so-called sandwich-flushing brick, which is also installed instead of a conventional brick of the refractory lining of the converter. In the abutting surfaces of the refractory individual parts longitudinal grooves or profiled metal inlays are provided, by which the cavities conducting the flush gas are formed. In addition to the fact that such a sandwich-flushing brick is also very complicated and expensive in its production, it has the disadvantage that a change in the gas permeability may occur during the time of its use, if an individual part becomes detached from its neighbouring individual part or from the sheet or plate jacket. Furthermore, early wear cannot be avoided, since the refractory individual parts have a composition different from that of the refractory bricks of the inner lining.